As various Undertale fans have pointed out online, Deltarune is an anagram for Undertale and refers to the symbol on Undertale NPC Toriel's tunic.

Deltarune's website contains several warnings in English and Japanese about things like overriding security protocols and refraining from discussing "the program" for 24 hours in the interest of public safety.

The site says these warnings are the final ones players will receive before encouraging them to take things into their hands and allowing them to download Deltarune for PC or Mac.

Exit Theatre Mode

Fox first teased Deltarune yesterday morning. He blacked out Undertale's thumbnail image on Twitter and tweeted that it was "really important" for players who completed Undertale to return and check back in 24 hours. "I want to make something new, and it all begins with your feedback," wrote Fox of the tease.